Gear tester



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GEAR TESTER Filed March 9, 1944 s Sheets-Sheet 1 NNAR G. WIDEN J. ELGERU INVENTORSI- L A n N E m w G G GEAR TESTER Filed March 9, 1944 .6 Sheets-Sheet 2 MASTER WORM WHEEL 76 |m mmummmn UNNAR G. ROBERT J.

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N E w ELGERUD a. G. WIDEN EIAL. l 7A GEAR TESTER 6 Sheets-Sheet 3 IIVVE/V TORSI- 3948- s. e. WIDEN mm. 2,447,445

GEAR TESTER Filed March 9, 1944 6 Sheets-Sheet 5 66 //v VE/V 70/?53- @UNMAR Q.

Aug. 17, 19%. G. 5. WIDEN ETAL GEAR TESTER Filed March 9, 1944 6 Shqets-Sheat 6 SLIDE IS BACK CHANGE OF GEARS.

FOR

FAST FEED FORWARD.

BEGINNING OF FINE FEED.

FINE FEED CLEARANCE FOR PLUS OR MINUS RUNOUT.

//VV/V7'0R$.- GUNNAR G BERT J. HELGERUD .WEDEN iarrr.

'. This invention relates to gear testers.

An object ofthe invention is the provision of Patented Aug. 17, 1948 I GEAR TESTER; Gunnar Grwiden and Robert .I. Hel er-ad, Minneapolls,

Mlnn., assignors to General Mills, Inc.,

a corporation of Delaware Application March 9, 1s44,'sena1'No. 525.142

simple, rapid, accurate and efficient means for testing the accuracy of gears of various kinds.

This and other objects as will hereinafter appear are accomplished by this invention which is fully described inthe following specification and shown in the accompanying drawings in which Figure 1 is a perspective view of one form of thegear tester for use in testing the accuracy of worms and worm wheels;

Fig. 2 is a partial enlarged view similar to Fig. 3 is a similar view showing the worm wheel out of mesh with the worm;

- Fig. 4 is a longitudinal vertical section through Fig. 1;

Fig. 5 isa partial enlarged perspective view from the rear of the head-stock of Fig. 1;

Fig. 6 is a partial vertical section on the line (3 of Figs. 4 and 5;

- Fig. 7 is an enlarged section on the line 7-? of Fig 4;

Fig. 8 is an enlarged partial the crank at the top of Fig. 4;

Fig. 9 is a side elevation of a standard worm for testing worm wheels;

Fig. 10 is a longitudinal wheel for testing worms;

verticalsection on section of a worm Fig. 11 is similar to Fig. 1, but viewed from the opposite side and showing the machine rigged for testing spur gears;

Fig. 12 is a partial enlarged vertical section on the line 12 oi Fig. 11;

Fig. 13 is an enlarged perspective of the adapter used in the rotatable head as shown in Fig. 11;

Fig. 14 is a section on the line it of Fig. 13; Fig. 15 is a partial enlarged front elevation of a rotatable plate of Fig. 1 showing some of the parts in section;

Fig. 16 is a partial horizontal section taken on the line iii-i6 of Fig. 15;

Figs. 17 and 18 are transverse sections on the lines 11 and E8 of Fig. 16;

Fig. 19 is a view similar to Fig. 9 showing a special jig for testing worms;

Fig. 20 is a partial enlarged vertical section on 3 Claims. (CL 33-4795).

Fig. 23 is a partial vertical section through the carriage showing the latter backed away and the worm wheel out ot'mesh with the worm; and

Figs. 24 to 27, inclusive, are similar views showing diagrammatically the several steps of bringing the gears gradually into mesh.

The embodiment illustrated comprises a gear tester having a base in which is mounted a plate A rotatable about a horizontal axis and a carriage or slide B slidable horizontally axially of the plate. Means are provided. as will later be explained, for mounting one gear to be tested on the plate and the meshing gear on the carriage, aswell as meansfor accurately measuring the "runout or inaccuracies of the gears as they are rotated about fixed axes. Usually, a gear to be tested is measured when meshed with a mast'er gear of known accuracy. Thus the readings obtained show the accuracy of the gear to be tested. Various types of gears, such as worm and worm wheel, spur gears, bevel gears, etc., can be tested-in pairs with this gear tester.

'On the base is bolted a head casting 32 (Fig. 4) in which is slidably mounted a shaft housing M which slides vertically in guideways 35, 35 (Fig. 16) in the head-stock and which is moved up and down by means of a screw 36 and a crank 38. The screw is journalled in members at, 12 and has a shoulder it preventing longitudinal movement. A collar 46 (Fig. 8) is graduated and is made adjustableby means of a screw t8 and a wedge pin 69. A shaft 50 (Fig. 4) carrying the plate A is journalled in suitable ballbearings in the housing 3% so as to rotate about a horizontal axis and is surrounded by a brake band 52 which has a screw 54 (Fig. 6) for locking the band on the shaft so that the shaft can be locked in any adjusted position. An eccentric shaft 56 and lever 58 (Fig. 16) also serve to lock the housing 34 in any adjusted position vertically. Various jigs for holding gears to be tested on the plate A will later be described.

A tail-stock 60 (Figs. 4 and 20) is mounted on the base and is slidable thereon between guides 62, 6t axially of the shaft 50. It is movable by means of a screw 66 and a crank Stand may be locked in adjusted position by means of a lever 10- keyed "on an eccentric shaft 72 journalied in the'tail-stock and carrying a link it passing through a brake shoe l6 slidable with the tailstock in the base.

The carriage B is slidable the tail-stock between carefully ground and ad- Justed guides at; 82 on one side and. 86 on the other.- This carrlage'is urged'to the left in- Fig:

back and forth in 3 4 by means of a spring ll, one end at which is secured to the lower end of an adjustable bolt which passes up through a slotted bar $2 on the carriage, the screw being secured at any adjusted position by means of a knurled nut it to adjust the tension of the spring 00. A vertical finger on stop 98 is adiustably secured to the carriage or slide by means of a knurled nut 00. This ringer is adapted to engage a contact pin I00 of a dial gauge I02. This, dial gauge is adapted to read movements of the contact pin to one ten-thousandths of an inch. The purpose of this will presently be apparent.

A short vertical stub axle or arbor IN is carried by the carriage, the axis of which is at right angles to the axis of the worm I00. On this axle is rotatably mounted a worm wheel I08 to be tested. The corresponding worm I00 (Fig. 16) is mounted for rotation on conical centers H0, H2 which are slidably mounted in alignment in blocks H4, H6 and are urged toward each other by means of springs H0 and the operatormay rotate them or adjust them by means of knobs I20 and when adjusted they are locked by means of screws I22'(Fig. 17). The blocks III, H8 are slidably mounted between guides I24, I20 and these blocks may each be locked in place by means of a locking lever I28 on an'eccentric shaft I30 operating a link I02 on a brake shoe I". The plate A is graduated on its periphery and provided with a Vernier at the top so that it can.

be set accurately at any position, particularly with the centers H0, 2 horizontal or vertical.

Thus it will be understood that where worm wheels I05 are to be tested they will be mounted on the stub axle I04 as shown in Fig. 3 and that the corresponding worm I08 is a standard .worm which has been accurately ground and measured so that'by rotating the two in mesh, the worm wheel can be tested. When the worm wheel is moved into mesh with this standard worm, this is done by means of a crank 0 which normally stands in the position shown in'Fig. 23 in which the carriage is retracted so as to hold the gears out of mesh. This crank is keyed on a shaft I42 which carries a cam I which bears against a block M5 depending from the carriage B. As the crank I is slowly rotated in a counterclockwise direction, as shown in Figs. 24 to 27, the carriage moves to the left first at a fairly rapid pace and then more slowly asthe lower portion of the cam I comes in contact with the block I46. The carriage is so adjusted that when the worm I06 is in mesh with the worm wheel I08 (Fig. 27) the cam I is out of contact with the block I48. In fact, the clearance between the cam and block at this point must be great enough that no amount of inaccuracy or runout" in the worm will permit them to come in contact as the worm and worm wheel are rotated while held yieldably in mesh by the spring 88.

The method of operation of this form of the device is as follows. carefully ground and calibrated so that its irregularities, if any, are known. This worm is then placed between centers II2 whichare then set accurately in a horizontal position by means of the graduations on the periphery of plate A. A hand wheel I0! is secured thereon for turning the worm. The centers are then clamped by means of the screws I22 so as to eliminate errors due to variation in distances between these centers. A worm wheel I06 to be tested is placed on the axle I 04 and the carriage so adjusted that he worm wheel will stand away irom the worm,

A standard worm as I08 is as shown in Fig. 23, when the carriage or slide is drawn back and so that the block I will be out of contact with the cam I when the gears are fully in mesh as shown in Fig. 27. The pressure exerted at this time will depend upon the tension or the spring 80 which may be adjusted to suit the conditions of the test as is shown by experience.

At this time the finger 88 has pressed in the contact pin I00 oi the dial gauge I02. The dial gauge can then be adjusted to zero, as shown in Fig. 2, by rotating the face of the dial in a manner well known with this type of instrument. The operator then turns the worm 100, by means oi! the hand wheel I00, thereby rotating both the worm and the worm wheel. At the same time he observes the readings of the dial indicator to see whether the pointer shows either plus or minus variations and how much. He keeps rotating the worm until the worm wheel has made a complete revolution and if the variations noted are less than the allowable variations for that particular worm wheel, it will be Passed as satisiactory. J

Referring-to Figs. 23 to 27, inclusive, it will be noted that the cam I first moves the carriage or slide rapidly toward the master worm I08 and then more slowly so that when the two come into mesh the motion or the worm wheel is very The crank I40 in Fig. 23 holds the carriage back with the spring 88 in tension. In Fig. 2'? the cam I44 is out of contact with the block I48 and the spring 88 holds the worm against the worm wheel.

Fig. 19 shows a modification of the worm where the worm itself is to be tested for accuracy against a standard or master worm wheel. In this case the worm 208 is mounted on aspecial arbor 2| I, one end of which is screw-threaded to receive a locking nut 2I3. A hand wheel 200 serves as before to rotate the worm. The ends of the arbor are drilled to receive the conical centens I I0, I I2, as before.

Reading the helix angle of the worm is done by turning the plate A in one direction until the worm in engagement with a standard .worm wheel will turn no further and reading the peripheral scale in degrees, then turning the plate A in the opposite direction as'iar as it will go and again reading its angle. From the average of these two readings the helix angle can be calculated.

The operation of testing the accuracy of this worm is quite similar to that previously described for testing the worm wh'eel.

In Figs. llthrough 14 is shown a modified form of the device for use in testing spur gears. In this a block M6 is slidably mounted in radial guides in the plate A in substantially the same way as previously described for the block H8 and is locked by a lever 228 corresponding to the lever I28 01 Fig. 18. This block carries an arbor 2I5 which is adapted to accurately fit the bore in a gear 2. A corresponding mating gear M9 is similarly mounted on an arbor 22 Iin the carriage B which is otherwise substantially the same as the carriage B of Fig. 4. The plate A is then turned to a position 90 from that shown in Fig. 4 so that the axes of the arbors 2I5 and HI are parallel. H

The arbor M is preferably tapered and placed into a tapered hole in the adapter 2l6. To keep this hole clean and to provide for removing this axle we have secured a plate 223 to the adapter by screws and a screw 225 is threaded through the plate in axial alignment with the stub axle 2I5 for removing it. The same is true of the stub axle 22L The testing of the gears 2H, 2l9, one ofwhich is a master gear while the other is the product to be tested, proceeds in much previously described for the worm and the worm wheel except that in this case the operator turns the gear 2 by hand, at the same-time noting the plus and minus readings of the dial indicator.

In Fig. 21 is shown still another modification of the gear tester with adapters arranged for testing bevel gears. Here again, either gear 3| I or 3!!! may be the master gear while the other is the gear to be tested. The adapter 323 secured to the carriage B by screws .thus carries a stub axle 32| which is horizontal and parallel to the axis of the plate A and adapted to receive the gear 3l9. The block 3| 4 corresponds to the block i I 4 of Fig. 16 and carries a stub axle 3l5 for the gear 3. The plate A is then turned so as to place the axis of the axle 3i5 vertical and at right angles to the arbor 32 I. A wear spacer 325 is used to reduce wear on the gear 3".

The method of testing these bevel gears is substantially the same as that described'for the spur gears. Should the axis of the worm and the worm wheel not be 90 as shown in Fig. 1, the plate A can be turned to any angle assumed by the axis of the worm with respect to the axis of the worm wheel.

Thus it will be seen that we have provided a very simple, rapid, accurate and ,efllcient means for testing gears of various kinds and one which can be varied in numerous ways to adapt itself to different combinations of gears.

While we have shown and described but a few embodiments of our nvention, it is to be understood that it is capable of many modifications. Changes, therefore, may be made which do not depart from the spirit and scope of our invention as disclosed in the appended claims.

We claim as our invention:

1. Gear testing apparatus comprising a main frame, a plate rotatable about an axis in the main frame, means on the plate for rotatably mounting a gear for rotation at right angles to the axis of the plate, a carriage slidable axially toward and from the plate, a spring for urging the carriage toward the plate, cam means opposing the spring for moving the carriage, the angle of the cam being less steep as the gears approach each other, means on the carriage for mounting a gear for meshing with the first-mentioned gear, and

the same way as means for measuring movements of the carriage as the gears are rotated.

2. Gear testing apparatus comprising a main frame, a plate rotatable about an axis in the main frame, means on the plate for rotatably mounting a gear for rotation at right angles to the axis of the plate, a carriage slidable axially toward and from the plate, a spring for urging the carriage toward the plate, cam means opposing the spring for moving the carriage, the angle of the cam being less steep as the gears approach each other, means on the carriage for mounting a gear for meshing with the first-mentioned gear, a dial indicator carried by the main frame and having a contact point, and a finger on the carriage adapted to engage the contact point to indicate movements of the carriage due to runout of the gears.

3. Gear testing apparatus comprising a main frame, a plate rotatable about an axis in the main frame, means on the plate for rotatably mounting a gear for rotation at right angles to the axis of the plate, a carriage slidable axially toward and from the plate. a spring for urging the carriage toward the plate, cam means opposing the spring for moving the carriage, the angle of the cam being less steep as the gears approach each other, means on the carriage for mounting a gear for meshing with the first-mentioned gear, a dial indicator carried by the main frame and having a contact point, a finger on the carriage adapted to engage the contact point to indicate movements of the carriage due to runout of the gears, the cam being mounted on a horizontal shaft, and a crank so mounted on said shaft that the crank hangs substantially vertically when the cam is engaged and moves through an angle of about 280 to a point below horizontal when the cam is withdrawn.

GUNNAR G. WIDEN. ROBERT J. HELGERUD.

REFERENCES CITED The following references are of record in the 

